Recent progress in microarray technology has been related to the development of high resolution microarrays which can map genomic alterations and constitutional variants in DNA copy number at an extremely high resolution. We have applied high resolution arrays in this fashion to several systems and have also adapted this technology to the mapping of DNase I hypersensitive sites. Recently, we have demonstrated that they can be used to map DNA origins of replication. We have also worked to push the limits of detection by extending sample types to formalin fixed, paraffin embedded samples and flow sorted primary cells. We have established that useful nucleic acid preparations can be obtained from fixed tissues and are continuing to extend the analysis of this material for a wider range of genomic technologies. Current efforts have been directed primarily at the implementation of next generation sequencing technologies. These methods primarily depend on producing an array of DNA molecules which are sequentially imaged during the sequencing reaction. We are investigating the use of these methods for gene expression profiling for large and small RNAs, for the detection of genome rearrangements, mutations, and for the measurement of chromatin modifications, DNase I hypersensitive sites, and transcription factor localization. A major part of this effort is the development of a powerful computational environment which can be used to analyze the massive amount of sequence data which is generated by this work. Although this is a challenging process, it ultimately will yield a streamlined analysis pipeline in which multiple sequence based assays will be easy to integrate and free of array platform specific artifacts. Specific goals of our computational efforts include the optimization of pipelines to process sequence data for chromatin analysis, chromosome rearrangements, gene expression, and mutation detection. We are currently engaged in pursuing new approaches to target sequencing efforts to the small proportion of the genome composed of genes in order to be able to sequence thousands of genes in individual samples and in a complementary fashion, to sequence a few key genes in hundreds of samples. These are goals are being accomplished with the aid of thousands of synthetic oligonucleotides which are used to target the desired portion of the genome.